St. John USVI Fauna: Hermit Crab
A Virgin Island riddle challenges you to identify the creature that has the following characteristics: "I live on land and walk about, but always home, in or out."
The answer is the hermit crab, which can indeed be found just about anywhere on St. John walking about, always carrying its home along with it.
The hermit crab also known locally as soldier crab is scientifically named Coenobita clypeatus. Its home is usually a shell commandeered from the West Indian top snail, better known as the whelk, although shells of other mollusks and even small bottles will do in a pinch. The hermit crab firmly attaches itself to its stolen shell by means of two hooks located on its soft abdomen. It will not let go even if you forcibly try to pull it out. It will hold tight to the death, letting its body be torn apart.
The hermit crab, like other members of the crab family, is a decapod, meaning ten footed. Two of its "feet", however, are actually claws, one of which is usually about three times larger than the other. The claws are used for battle, for defense, and to procure food. The hermit crab's eyes are located at the ends of two short eyestalks. The hermit crab can stick most of its body out of its shell to walk around or it can withdraw totally inside using its large claw as a door, which closes off the opening.
The only time a hermit crab leaves its protective shell is when it outgrows it. The crab then seeks a new and larger one. Because it is very vulnerable outside its shell, the hermit crab makes sure that its new home is absolutely suitable before relocating. It closely examines and inspects its new prospective residence with its legs and feelers before making the dangerous exit from one shell and entrance to the next and the exchange is done very quickly once the decision is made. When shell pickings are scarce, hermit crabs can use any convenient item as a home. John Gibney reports that in his youth he saw hundreds of hermit crabs walking around in old baby food jars that his father had been saving.
Competition for new shells is keen and hermit crabs will often steal shells from one another. They will engage in fierce battles, fought to the death, for the possession of an appropriate shell. The loser of the engagement not only loses its life but will be eaten by the victor. It is because of this tendency towards fighting one another that the hermit crab is alternately named "soldier crab".
The Hermit crab is predominantly a land creature, but it still has close ties to water and the sea. In fact it can never be entirely away from water, and solves this problem by always carrying a supply of water in its shell. Moreover, the hermit crab returns to the sea in order to reproduce. At certain times of the year hundreds of these creatures scramble and tumble down the mountainsides and make their way to the seashore where the females crawl to the water's edge. They then cast their fertilized eggs in the sea where the newly born hermit crabs spend their next few months before returning to land.
Hermit crabs are not eaten by human beings, but they do provide people with other benefits. Hermit crabs will eat almost anything. The more disgusting, the better they like it. Choice items are discarded organic material from garbage, compost pile goodies, and various varieties of feces. Thus hermit crabs become an effective army of walking garbage recyclers. In addition, local fisherman often use hermit crabs for bait, either by taking them out of their shells and putting them on a hook, or by crushing them up with sand and then using the mixture for chum to attract fish to an area.
Hermit crabs have another use, although not yet exploited in St. John; they are sold on the United States mainland and in Europe as pets. They are sold, however, with the following warning: "Temperament - Usually good tempered but can pinch hard when handled."Soldier Crab Saga By Rafe Boulon
Video of Hermit Crabs Mating